SYNTHESIS AND CHARACTERIZATION OF n-CdSe THIN FILMS DEPOSITED AT DIFFERENT SUBSTRATE TEMPERATURES

The n-CdSe thin films of thickness 1000 nm were fabricated on glass substrate at different temperatures by electron beam evaporation technique using optimized source material of composition Cd0.60Se0.40. The substrate temperature was in the range of 298K to 423K. These thin films were characterized by electrical, optical and structural measurements. The temperature dependent electrical, optical and structural properties are discussed. The X-ray diffraction (XRD) study reveals that for all the films preferred orientation plane was (002). The lattice constant, grain size, strain and dislocation density of the films were calculated and studied their variation with substrate temperature. The scanning electron microscope (SEM) study indicates that grain size increases with increase of substrate temperature. The direct band gap was calculated using absorption coefficient which is measured in the wavelength range 400nm to 700nm and found that the direct band gap varies between 1.48 eV to 1.38 eV with substrate temperature.